This README is just a fast *quick start* document. You can find more detailed documentation at [redis.io](https://redis.io).
What is Redis?
--------------
Redis is often referred to as a *data structures* server. What this means is that Redis provides access to mutable data structures via a set of commands, which are sent using a *server-client* model with TCP sockets and a simple protocol. So different processes can query and modify the same data structures in a shared way.
Data structures implemented into Redis have a few special properties:
* Redis cares to store them on disk, even if they are always served and modified into the server memory. This means that Redis is fast, but that it is also non-volatile.
* The implementation of data structures emphasizes memory efficiency, so data structures inside Redis will likely use less memory compared to the same data structure modelled using a high-level programming language.
* Redis offers a number of features that are natural to find in a database, like replication, tunable levels of durability, clustering, and high availability.
Another good example is to think of Redis as a more complex version of memcached, where the operations are not just SETs and GETs, but operations that work with complex data types like Lists, Sets, ordered data structures, and so forth.
If you want to know more, this is a list of selected starting points:
* Introduction to Redis data types. http://redis.io/topics/data-types-intro
* Try Redis directly inside your browser. http://try.redis.io
* The full list of Redis commands. http://redis.io/commands
* There is much more inside the official Redis documentation. http://redis.io/documentation
Building Redis
--------------
Redis can be compiled and used on Linux, OSX, OpenBSD, NetBSD, FreeBSD.
We support big endian and little endian architectures, and both 32 bit
and 64 bit systems.
It may compile on Solaris derived systems (for instance SmartOS) but our
support for this platform is *best effort* and Redis is not guaranteed to
work as well as in Linux, OSX, and \*BSD.
It is as simple as:
% make
To build with TLS support, you'll need OpenSSL development libraries (e.g.
libssl-dev on Debian/Ubuntu) and run:
% make BUILD_TLS=yes
To build with systemd support, you'll need systemd development libraries (such
as libsystemd-dev on Debian/Ubuntu or systemd-devel on CentOS) and run:
% make USE_SYSTEMD=yes
To append a suffix to Redis program names, use:
% make PROG_SUFFIX="-alt"
You can run a 32 bit Redis binary using:
% make 32bit
After building Redis, it is a good idea to test it using:
% make test
If TLS is built, running the tests with TLS enabled (you will need `tcl-tls`
installed):
% ./utils/gen-test-certs.sh
% ./runtest --tls
Fixing build problems with dependencies or cached build options
---------
Redis has some dependencies which are included in the `deps` directory.
`make` does not automatically rebuild dependencies even if something in
the source code of dependencies changes.
When you update the source code with `git pull` or when code inside the
dependencies tree is modified in any other way, make sure to use the following
command in order to really clean everything and rebuild from scratch:
make distclean
This will clean: jemalloc, lua, hiredis, linenoise.
Also if you force certain build options like 32bit target, no C compiler
optimizations (for debugging purposes), and other similar build time options,
those options are cached indefinitely until you issue a `make distclean`
command.
Fixing problems building 32 bit binaries
---------
If after building Redis with a 32 bit target you need to rebuild it
with a 64 bit target, or the other way around, you need to perform a
`make distclean` in the root directory of the Redis distribution.
In case of build errors when trying to build a 32 bit binary of Redis, try
the following steps:
* Install the package libc6-dev-i386 (also try g++-multilib).
* Try using the following command line instead of `make 32bit`:
`make CFLAGS="-m32 -march=native" LDFLAGS="-m32"`
Allocator
---------
Selecting a non-default memory allocator when building Redis is done by setting
the `MALLOC` environment variable. Redis is compiled and linked against libc
malloc by default, with the exception of jemalloc being the default on Linux
systems. This default was picked because jemalloc has proven to have fewer
fragmentation problems than libc malloc.
To force compiling against libc malloc, use:
% make MALLOC=libc
To compile against jemalloc on Mac OS X systems, use:
% make MALLOC=jemalloc
Verbose build
-------------
Redis will build with a user-friendly colorized output by default.
If you want to see a more verbose output, use the following:
% make V=1
Running Redis
-------------
To run Redis with the default configuration, just type:
% cd src
% ./redis-server
If you want to provide your redis.conf, you have to run it using an additional
parameter (the path of the configuration file):
% cd src
% ./redis-server /path/to/redis.conf
It is possible to alter the Redis configuration by passing parameters directly
as options using the command line. Examples:
% ./redis-server --port 9999 --replicaof 127.0.0.1 6379
% ./redis-server /etc/redis/6379.conf --loglevel debug
All the options in redis.conf are also supported as options using the command
line, with exactly the same name.
Running Redis with TLS:
------------------
Please consult the [TLS.md](TLS.md) file for more information on
how to use Redis with TLS.
Playing with Redis
------------------
You can use redis-cli to play with Redis. Start a redis-server instance,
then in another terminal try the following:
% cd src
% ./redis-cli
redis> ping
PONG
redis> set foo bar
OK
redis> get foo
"bar"
redis> incr mycounter
(integer) 1
redis> incr mycounter
(integer) 2
redis>
You can find the list of all the available commands at http://redis.io/commands.
Installing Redis
-----------------
In order to install Redis binaries into /usr/local/bin, just use:
% make install
You can use `make PREFIX=/some/other/directory install` if you wish to use a
different destination.
Make install will just install binaries in your system, but will not configure
init scripts and configuration files in the appropriate place. This is not
needed if you just want to play a bit with Redis, but if you are installing
it the proper way for a production system, we have a script that does this
for Ubuntu and Debian systems:
% cd utils
% ./install_server.sh
_Note_: `install_server.sh` will not work on Mac OSX; it is built for Linux only.
The script will ask you a few questions and will setup everything you need
to run Redis properly as a background daemon that will start again on
system reboots.
You'll be able to stop and start Redis using the script named
`/etc/init.d/redis_<portnumber>`, for instance `/etc/init.d/redis_6379`.
Code contributions
-----------------
Note: By contributing code to the Redis project in any form, including sending
a pull request via Github, a code fragment or patch via private email or
public discussion groups, you agree to release your code under the terms
of the BSD license that you can find in the [COPYING][1] file included in the Redis
source distribution.
Please see the [CONTRIBUTING][2] file in this source distribution for more
information.
[1]: https://github.com/redis/redis/blob/unstable/COPYING
[2]: https://github.com/redis/redis/blob/unstable/CONTRIBUTING
Redis internals
===
If you are reading this README you are likely in front of a Github page
or you just untarred the Redis distribution tar ball. In both the cases
you are basically one step away from the source code, so here we explain
the Redis source code layout, what is in each file as a general idea, the
most important functions and structures inside the Red